Ball joint

ABSTRACT

A ball-and-socket joint, especially a wheel guide joint for motor vehicles is provided with a housing ( 1 ), in the cavity ( 2 ) of which, which is open on at least one side, a bearing shell ( 3 ) is inserted with a joint ball ( 4 ) mounted therein. The bearing shell ( 3 ) forms a assembly unit ( 3,4 ) together with the joint ball ( 4 ) accommodated therein. The assembly unit is displaceable in the cavity ( 2 ) along a axis ( 6 ). A first collar ( 7 ) and a second collar ( 8 ), between which a limited free path ( 5 ) of the displaceable assembly unit ( 3, 4 ) is defined, form end stops in the cavity ( 2 ) of the housing ( 1 ). The bearing shell ( 3 ) is a accomodated in the cavity ( 2 ) under a slight radial pretension and at least one compensating element ( 15 ) is arranged between the bearing shell ( 3 ) and the inner surface of the cavity ( 2 ).

FIELD OF THE INVENTION

The present invention pertains to a ball-and-socket joint especially fora wheel guide joint for motor vehicles with a housing with a cavitywhich is open on at least one side. A bearing shell is inserted with ajoint ball mounted therein. The bearing shell forms an assembly unittogether with the joint ball accomodated therein. The assembly unit isdisplaceable in the cavity along an axis. A first collar and a secondcollar, between which a limited free path of the displaceable assemblyunit defined, form end stops in the cavity of the housing.

BACKGROUND OF THE INVENTION

Such a ball-and-socket joint, as is known, e.g., from U.S. Pat. No.6,042,294 or U.S. Pat. No. 6,010,272 and can be used as a wheel guidejoint for motor vehicles, comprises a housing, which has a cavity thatis open on at least one side. A bearing shell with a joint ball mountedtherein is inserted into this cavity.

In solutions according to the documents cited, the bearing shell isdisplaceable together together with the joint ball accommodated by it inthe cavity along an axis coinciding with the axis of symmetry of thebearing shell, and a first collar and a second collar, between which alimited free path of the displaceable bearing shall is thus defined,form end stops in the cavity of the housing, so that the assembly unitcomprising the bearing shell and the joint ball can be moved slidinglyto and fro between the first collar and the second collar of thehousing. Slide bearings have a clearance, which is called “bearingslackness,” between the bearing surfaces sliding on one another. Thisbearing slackness is the cause that the combination of a slide bearingwith a ball-and-socket joint has been able to be solved onlyunsatisfactorily so far. The ball-and-socket joint embodiments accordingto U.S. Pat. No. 6,042,294 or U.S. Pat. No. 6,010,272 also fail to offera satisfactory solution to this.

Another problem is that especially the ball-and-socket joints in thewheel carrier of a motor vehicle are subject to high thermal loads.These stem from adjacent components, such as the brakes, and have alasting affect on the mounting characteristics. Even though heatprotection shields are sometimes meaningful, they cannot permanentlyprotect the ball-and-socket joints, so that there is a need for jointsthat have an approximately constant mounting characteristic despiteextreme temperature changes. These difficulties in prior-artball-and-socket joints increase with increasing outside temperature andare additionally intensified by the temperature effects on thecomponents receiving the ball-and-socket joint in the motor vehicle.

SUMMARY OF THE INVENTION

The technical object of the present invention can be considered to be toprovide a ball-and-socket joint that effectively compensates shape,position and location tolerances as well as deformations of thecomponents of the ball-and-socket joint which are caused by thermal loador by the action of external forces.

According to the invention, a ball-and-socket joint is provided,especially for a wheel guide joint for motor vehicles with a housingwith a cavity which is open on at least one side. A bearing shell isinserted with a joint ball mounted therein. The bearing shell forms anassembly unit together with the joint ball accommodated therein. Theassembly unit is displaceable in the cavity along an axis. A firstcollar and a second collar, between which a limited free path of thedisplaceable assembly unit is defined, form end stops in the cavity ofthe housing. The bearing shell is accomodated in the cavity under aslight radial pretension and at least one compensating element isarranged between the bearing shell and the inner surface of the cavity.

A completely new approach is taken in the present invention. It isdesirable and also achieved here by the embodiment according to thepresent invention that the bearing shell can move together with thejoint ball mounted by it within the housing. Consequently, there is asliding connection between the outer surface of the bearing shell andthe inner surface of the cavity of the housing, in which the bearingshell is accommodated. This solution, which is known per se, is improvedaccording to the present invention by the bearing shell beingaccommodated in the cavity of the housing under a slight radialpretension, i.e., by the bearing shell being correspondingly supportedat the walls of the cavity. This can be imagined, e.g., such that atleast one compensating element is arranged between the outer surface ofthe bearing shell and the inner surface of the cavity.

The bearing shell may be displaceable together with the joint ballaccommodated by it in the cavity along an axis, and the location of theaxis does not necessarily have to coincide with the axis of symmetry ofthe bearing shell. Rather, an inclination of the axis within the jointhousing is also within the scope of the present invention.

Both shape and position tolerances of the ball-and-socket joint anddeformations of the components of the ball-and-socket joint which arecaused by thermal loads or by the action of external forces can beeffectively compensated with such a ball-and-socket joint design.Moreover, a ball-and-socket joint was created that is free fromclearance in the radial direction.

Thermal stresses and, to a lesser extent, even bending, e.g., thesagging of the wheel carrier as a consequence of lateral forces actingon the wheel carrier, can be compensated. The ball-and-socket joint,designed as a movable bearing, transmits radial forces and thus improvesthe lateral guiding of the wheel of the motor vehicle, which is ofconsiderable advantage especially at the beginning of travel and duringbraking.

According to one embodiment of the present invention, theabove-mentioned radial pretension can be generated by recessing at leastone groove in the outer surface of the bearing shell and inserting acompensating element into each groove.

To generate the radial pretension as uniformly as possible, it ismeaningful to provide at least two parallel grooves located at spacedlocations from one another with compensating elements inserted in them.

The outer dimensions of the compensating element or the compensatingelements should be slightly larger than the inner dimension of thecavity of the housing. For example, a slightly crowned outer dimensionof each compensating element is particularly advantageous, and thecompensating element should have at least a limited elasticity.

The housing of a ball-and-socket joint according to the presentinvention can be made open on one side or on both sides. In the case ofa housing open on one side, it is possible to use the bottom of thehousing as a second collar.

Furthermore, it is considered to be meaningful to provide, on a housingthat is open on both sides, a first collar, which comprises, e.g., apart of the housing edge directed toward the inside of the joint, and asecond collar, which may be designed as a radial flange area of aclosing element.

Any component that is able to protect the sensitive inner parts of thebearing from contaminants or from the penetration of moisture may beused as a closing element. For example, sealing bellows made of rubbermaterials have been known.

Corresponding to a further suggestion, the closing element inserted intoa mount of the housing may be fixed by the deformation of a materialbead of the housing edge at the housing, which takes place during theclosing of the ball-and-socket joint.

The closing element may have a one-part design, but it may also have amultipart design and comprise, e.g., a closing ring and a coversealingly connected to same. It is recommended that at least one sealingelement be used to improve the sealing between the closing ring and thecover. A round ring made of rubber shall be mentioned here only as anexample of such a sealing element.

In further embodiments of the present invention, the joint ball may beconnected detachably to a pivot. This offers the possibility ofconnection to components, which can be manufactured separately, in oneball pivot, which is especially useful if surface protection isnecessary on only one of these components and nevertheless offers thepossibility of a modular system, which makes it possible to manufacturethe ball pivot according to the needs from standardized individualparts.

Moreover, the pivot may also be designed as a component of a wheelcarrier of a motor vehicle. Due to this measure, i.e., the directconnection of the joint ball to a pivot made in one piece with the wheelcarrier, additional attached parts and consequently mounting operationscan be eliminated.

A special exemplary embodiment of the present invention will beexplained in greater detail below with reference to the drawings.

A special exemplary embodiment of the present invention will beexplained in greater detail below with reference to the drawings.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich a preferred embodiment of the invention is illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings,

FIG. 1 is a cross sectional view of a detail of a ball-and-socket jointaccording to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in particular, in the figure, a joint ball 4is placed on a pivot 14 of a wheel carrier 18. The joint ball 4 isdetachably connected to the pivot 14 by a screw connection 19.

With its spherical geometry having an equator defined as maximumdiameter perpendicular to an axis, the joint ball 4 is accomodated in ahomogeneous bearing shell 3, which has an inner geometry complementaryand conforming to the joint ball 4, above and below its equator. In theexample being shown, a cylindrical cavity 2, into which the bearingshell 3 is inserted in a slidingly movable manner, is present in ahousing 1 of the ball-and-socket joint, which housing is open on bothsides. When viewed in the direction of the axis 6, two circular grooves16 are recessed at axially spaced locations from one another into theouter surface of the bearing shell. The grooves 16 accomodate acompesating element 15 each. Each compensating element generates,relative to the axis 6, a radial pretension between the bearing shell 3and the inner surface of the cavity 2. Tolerance compensation is thusachieved and the bearing shell is prevented, furthermore, fromperforming a rotary movement around the axis 6. The radial rigidity,i.e., the damping properties of this ball-and-socket joint, can be sethighly accurately in the radial direction. It can also be determinedfrom the figure that the out circumference of the compensating element15 is crowned here, and a ring-shaped cross section was thereforeselected. This guarantees the absence of radial clearance, on the onehand, and, on the other hand, the easy axial mobility of the assemblyunit comprising the joint ball 4 and the bearing shell 3 within thecavity 2.

The housing 1 has, furthermore, a first collar 7 as well as a secondcollar 8 on the opposite side. The distance between these collars 7 and8 is selected to be greater than the height of the bearing shell 3.Thus, a free path 5 is left, which makes possible the axial mobility ofthe assembly unit comprising the bearing shell 3 and the joint ball 4 tofreely slide from a bottom position where the bearing shell contacts thesecond collar to a top position where the bearing shell contacts the topcollar.

In the exemplary being shown, a part of the housing edge directed towardthe inside of the joint is used as the first collar 7, and a radialflange area 20 of a closing element designated as a whole by 9 is usedas the second collar 8. The closing element 9 is of a multipart designin the disclosed embodiment for reasons of mounting. It comprises aclosing ring 11 and a cover 12 forming a driving fit with the closingring 11. For better sealing, a sealing element 13 was inserted betweenthe cover 12 and the closing ring 11.

During the mounting of the ball-and-socket joint, the closing ring 11 isfirst inserted with a radially directed flange area 20 into a mountinggroove 21 arranged on the inside of the housing. Deformation of amaterial bead 10 of the housing edge subsequently takes place during theclosing of the housing, as a result of which the closing ring 11 isfixed.

A heat protection shield 17 protects the components of theball-and-socket joint in the known manner from the harmful heatradiation of adjacent components. These are the brakes of the motorvehicle at the wheel carrier 18.

To optimize the sealing of the ball-and-socket joint against externaleffects, an elastic seal 23, whose outer elastic sealing surface 24 issupported against the heat protection shield of the ball-and-socketjoint, is inserted into a ring area 22. The seal 23 is arranged on thepivot side, i.e., on the side of the first collar 7 at the jointhousing, and the mounting may be performed by using a connectionincorporated into the material or by a positive-locking or nonpositiveconnection. To improve the elasticity, the seal 23 was made of a rubbermaterial, which has an insert 25 in this embodiment. The seal has,furthermore, a bead-like section 26.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

1. A ball-and-socket wheel guide joint for motor vehicles, the jointcomprising: a housing with a cavity open on at least one side and on atleast another side; a joint ball having an equator defined as a maximumdiameter perpendicular to an axis; a bearing shell inserted into saidhousing with said joints ball mounted therein, said bearing shell ishomogeneous and circles said equator in a conforming contact therebetween which extends below and above said equator and forms an assemblyunit together with said joint ball accommodated therein, said assemblyunit being movably mounted in said cavity along said axis; a firstcollar and a second collar defining a limited free path of said movablymounted assembly unit, said first collar and said second collar formingend stops in said cavity of said housing, said bearing shell is free toslide with said joint ball from a bottom position contacting said secondcollar to a top position contacting said first collar path; and acompensating element arranged between said bearing shell and an innersurface of said cavity, said compensating element biasing said bearingshell in said cavity under a slight radial pretension.
 2. Aball-and-socket joint in accordance with claim 1, wherein at least onegroove is recessed in the outer surface of said bearing shell and saidcompensating element is inserted into said groove and has an outerdimension that is slightly larger than an inner dimension of saidcavity;
 3. A ball-and-socket joint in accordance with claim 1, whereinsaid housing is open on both sides and said first collar is a part of ahousing edge directed toward an inside of the joint, and said secondcollar is radial flange area of a closing element; and said secondcollar is spaced from said joint ball.
 4. A ball-and-socket joint inaccordance with claim 3, further comprising: a mount of said housing,wherein said closing element is inserted into said mount of said housingand is fixed by a deformed material bead after the mounting of theball-and-socket joint.
 5. A ball-and-socket joint in accordance withclaim 3, wherein said closing element has a multipart design andcomprises a closing ring and a cover sealingly connected to said closingelement.
 6. A ball-and-socket joint in accordance with claim 5, furthercomprising a sealing element accomodated between said closing ring andsaid cover.
 7. A ball-and-socket joint in accordance with claim 1,further comprising a pivot, wherein said joint ball is detachablyconnected to said pivot, said pivot being part of a wheel carrier.
 8. Ajoint in accordance with claim 1, wherein: said assembly unit is movableinto contact with either said first collar or said second collar byforce applied to said joint ball along said axis.
 9. A joint inaccordance with claim 1, wherein: said cavity is a substantiallycylindrical cavity; said bearing shell has an outer surface whichdefines a circular groove and another circular groove spaced apartaxially; said compensating element is arranged in said circular groovesand another compensating element is arranged in said another circulargroove, said compensating element and said another compensating elementapply a radial force between said bearing shell and an inner surface ofsaid cavity.
 10. A ball-and-socket joint comprising: a housing with acavity open on at least one side and on at least another side; a jointball having an equator defined as a maximum diameter perpendicular to anaxis; a bearing shell inserted into said housing with said joint ballmounted therein, said bearing shell being homogeneous and circling saidequator in a conforming contact there between and extending below andabove said equator and forming an asembly unit together with said jointball accomodated therein, said assembly unit being movably mounted insaid cavity substantially along said axis; a first collar and a secondcollar defing a limited free path of said bearing shell that freelymoves with said joint ball from a bottom position where said bearingshell contacts said first collar to a top position where said bearingshell contacts said top collar, said first collar and said second collarforming end stops in said cavity of said housing; and a compensatingelement arranged between said bearing shell and an inner surface of saidcavity, said compensating element applying a slight radial pretension tosaid bearing shell.
 11. A ball-and-socket joint in accordance with claim10, wherein an outer surface of said bearing shell has a groove and saidcompensating element is inserted into said groove and has an outerdimension that is slightly larger than an inner dimension of saidcavity.
 12. A joint in accordance with claim 10, wherein: said assemblyunit is movable into contact with either said first or second stops byforce applied to said joint ball along said axis.
 13. A ball-and-socketjoint comprising: a joint ball; a bearing shell arranged around saidjoint ball, said joint ball and said bearing shell together forming anassembly unit, said bearing shell having an inner geometry substantiallycomplementary to said joint ball; a housing defining a cavity with anopening on one side and on another side of said housing, said openingand said cavity having an axial direction, said assembly unit beingmovably mounted in said cavity in said axial direction, said joint ballhaving an equator defined as a maximum diameter perpendicular to saidaxial direction, said bearing shell being homogeneous and circling saidequator in a conforming contact there between which extends below andabove said equator, said inner geometry of said bearing shell beingarranged on diametrically opposite sides of said maximum diameter; firstand second collars arranged in said cavity, said first and secondcollars limiting a path of movement of said assembly unit in said axialdirection, where said bearing shell is free to move with said joint ballfrom a bottom position where said bearing shell contacts said secondcollar to a top position where said bearing shell contacts said topcollar; and a compensating element arranged between said bearing shelland said housing, said compensating element radially biasing saidbearing shell inward.
 14. A ball-and-socket joint in accordance withclaim 13, further comprising: a heat protection shield arranged aroundsaid housing for shielding against adjacent components.
 15. A joint inaccordance with claim 14, wherein a wheel carrier is connected to saidjoint ball, said heat protection shield is connected to said wheelcarrier, and an elastic seal is arranged between said shield and saidhousing, said seal and said shield are arranged to seal said cavity openon at least one side from a surrounding environment.
 16. A joint inaccordance with claim 15, wherein said housing defines a ring areaaround said opening of said cavity, said elastic seal is arranged insaid ring area and mounted on said housing by using a connectionincorporated into the material or by a positive-locking or nonpositiveconnection, said elastic seal includes an elastic sealing surfacearranged against said heat protection sheild, said seal being formed ofa rubber material, and said seal including an insert and a bead section.17. A joint in accordance with claim 13, wherein said whole bearingshell is freely movable into contact with either said first or secondcollars by force applied to said joint ball in said axial direction. 18.A joint in accordance with claim 17, wherein said cavity is asubstantially cylindrical cavity, said bearing shell has an outersurface which defines two circular grooves spaced apart axially, andsaid compensating element is arranged in one of said grooves and anothercompensating element is arranged in the other of said grooves, saidcompensating element and said another compensating element apply aradial force biasing said bearing shell away from an inner surface ofsaid housing.
 19. A joint in accordance with claim 13, wherein saidcompensating element is indirect contact with an outer surface of saidbearing shell and a surface of said cavity.
 20. A joint in accordancewith claim 19, wherein said outer surface of said bearing shell definesa groove, and said compensating element is arranged in said groove. 21.A joint in accordance with claim 20, wherein said bearing shell isformed in one piece.
 22. A joint in accordance with claim 13, whereinsaid bearing shell is formed in one piece.
 23. A joint in accordancewith claim 13, wherein said inner geometry of said bearing shell issubstantially continuous.
 24. A joint in accordance with claim 13,wherein said geometry of said bearing shell forms a substantiallycontinuous bearing surface.
 25. A joint in accordance with claim 13,wherein said bearing shell is homogeneous.
 26. A joint according toclaim 13, wherein said bearing shell is freely moveable in two oppositedirections between said first and second collars.
 27. A joint accordingto claim 13, wherein said bearing shell is formed in one piece.
 28. Ajoint according to claim 13, wherein a pivot is connected to said jointball, and a heat-protection shield is arranged between said pivot saidjoint ball in said axial direction.
 29. A joint according to claim 28,wherein said heat protection shield is movable together with saidassembly unit in said axial direction relative to said housing.
 30. Ajoint according to claim 28, wherein said joint ball has a first endface, said pivot has a second end face facing said first end face, bothend faces being perpendicular to said axial direction, and said heatprotection shield is arranged between said first and second end facesand contacts said first and second end faces.